The present invention is directed to a printable sheet such as a business form having an integral label associated therewith which does not require a paper backing for the label. The invention is also directed to a method for making such a printable sheet.
In the manufacture of printable sheets such as business forms and children""s play mats, there are many circumstances in which it is desirable to form an integral, but ultimately separable, self-adhesive label as a part of the printable sheet. There are also many circumstances in which it is desirable to print on the self-adhesive label.
Conventional methods for the manufacture of printable sheets with integrated labels require either a) lamination of two webs of material, one for printing and the other to provide a backing for the label, or b) direct adhesion of a label laminate (label/adhesive/release layer/support) to the form. There are many variations of these two techniques. Where a label laminate is adhered to a paper sheet of a business form, it is typically applied on top of the paper sheet or edge thereof. See, for example, U.S. Pat. Nos. 4,865,669, 4,809,905 and 5,129,682. For the lamination techniques, a pressure-sensitive adhesive is typically applied to a portion of a paper sheet (first web) followed with a backing comprised of paper or similar material (second web) coated with release liner. A label is then cut from the paper sheet where the backing has been applied. Application of the pressure-sensitive adhesive and backing material with release liner is often accomplished simultaneously with the use of a transfer tape. The transfer tape is applied to the rear face of the paper sheet with the adhesive contacting the rear face of the paper sheet. Once the transfer tape is applied, the pressure-sensitive adhesive transfers from the tape to the paper sheet. Other examples of laminating techniques used to produce business forms with labels integrated therein are described in U.S. Pat. Nos. 5,507,901, 5,632,842 and 5,656,369. These laminating techniques, as well as methods for direct adhesion of labels to a form, require complex paper handling apparatus which must either align and adhere a label laminate to a paper sheet or align and adhere a paper sheet (first web) with a backing (second web) to provide the integrated label. In addition, where a second web is used, there is an increased risk of paper jams in printing equipment due to the increased thickness of the printable sheet at the label. There is also a risk of loss of the backing (second web) during printing or handling, resulting in exposure of the adhesive. Certain methods have specialized problems as well, for example, forms made with the use of transfer tape also have a tendency to curl and additional care is needed to flatten these forms.
The present invention overcomes the disadvantages of conventional methods and printable sheets with integrated labels in not requiring the alignment and adhesion of a separate (second) web to a paper sheet for the backing of the integrated label. In eliminating the need for a separate (second) web for the backing of the integrated label, the opportunity for a printable sheet to lose the backing is reduced and the opportunity for the printable sheet to jam printing equipment during use is also reduced.
The printable sheets of the present invention provide an integral label associated therewith and removable therefrom. This printable sheet comprises a base sheet having a front face and a rear face. The front face is capable of receiving print. The rear face is capable of having a pressure-sensitive adhesive adhere thereto and is also capable of receiving print for most embodiments. A pressure-sensitive adhesive layer is coated on a portion of the rear face of the base sheet and a solid silicone layer is coated over the pressure-sensitive adhesive. The solid silicone layer overlaps the pressure-sensitive adhesive so as to bond to the rear face of the base sheet by the overlapping portion. The solid silicone layer comprises ultraviolet light cured silicone polymers or electron beam cured silicone polymers which have been cured (crosslinked) in place over the pressure-sensitive adhesive and encapsulate the adhesive. The solid silicone layer provides a release face (surface) for the pressure-sensitive adhesive. At least one perforation or die cut is formed in a portion of the base sheet coated with pressure-sensitive adhesive on the rear face to define at least one removable layer.
The method of this invention produces a printable sheet such as a business form with removable labels and comprises providing a base sheet having a front face suitable for printing and a rear face suitable for adhering a pressure-sensitive adhesive. In most embodiments, the rear face is suitable for printing as well. A layer of pressure-sensitive adhesive is coated on a portion of the rear face of the base sheet. The layer of pressure-sensitive adhesive is coated with at least one layer of a liquid silicone resin coating formulation which cures to a solid upon exposure to ultraviolet light or electron beam radiation. The layer of liquid silicone resin coating formulation extends beyond the layer of pressure sensitive adhesive to the rear face of the base sheet. The coating of liquid silicone resin coating formulation is cured to a solid silicone layer by exposure to ultraviolet light or electron beam radiation. A portion of the base sheet having the pressure-sensitive adhesive and curable silicone resin on the rear face thereof is die cut or perforated in a pattern and at a depth which defines a removable label.